The present disclosure relates to improving the pressurization of a draught beverage (which may be alcoholic, for example lager) in a beverage container, such as a keg. However, other applications are contemplated, including medical applications and applications in a fluid system which dispenses beverages under controlled pressure.
Kegs hold fluid such as beer under pressure. One type of standard beer keg has a gas chamber and a separate beverage chamber, which may be separate physical spaces, configured as a gas space and a fluid space. A tap assembly includes a gas valve that allows the gas chamber to be pressurized with a gas, normally nitrogen for wine, and carbon dioxide (CO2) for beer or soda, and has a pressure regulator that passes the gas at a uniform pressure to the beverage chamber where it forms a gas head. A riser tube is connected through the tap assembly to a tap valve and extends down to a lower region of the beverage chamber so that when the tap valve is open the gas head pushes the beverage up the riser tube and out a spout of the tap valve.
Known methods of providing pressure to a gas chamber include manual pumped pressurized air systems and systems pressurized using external containerized sources of compressed gas. Externally pressurized systems are common in commercial systems that require heavy bottles of compressed CO2 gas that supply the compressed gas through regulators and pressure lines to pressurize one or more kegs.
Commercial retailers and other long-term dispensers of tap beer, such as taverns, clubs and bars, usually have an electrical pump for pressurizing beer kegs. Many also employ carbon dioxide under pressure in a tank for generating gas bubbles that form a thick head of foam on tops of beer in beer glasses and mugs. Some use either the electric pump or the pressure tank separately. A known drawback of the commercial systems is that they rely on electrically actuated pressure valves that do not allow the user to alter the pressure during regular use. A further drawback of the commercial systems is that they draw significant power, necessitating a connection to a power outlet.
Manually pumped pressurized air systems are common in consumer systems and typically rely on a manual air pump to pressurize the keg. Intermittent users and short-term users of beer kegs comprise a large portion of the market for tap beer. The kegs of beer is sold to the intermittent and short-term users through liquor stores and, where legal, through grocery stores and liquor departments of supermarkets. The same kegs or slightly larger ones with the same keg-faucet connectors are used for intermittent and short-term users and for commercial and long-term users. Instead of an electrical pump and/or a pressure tank, a hand pump on a hand-pump faucet of various types is used by the intermittent and short-term users. Many retailers of tap beer with relatively low sales volume also use the hand-pump faucet. A known drawback of the manually pumped pressurized air systems is that they are difficult to reliably maintain the pressure during regular use.
With particular reference to portable CO2-based dispensers, the pressure maintained in the keg is only crudely controlled via a manually-adjusted, mechanical pressure regulator. In such an arrangement, a decrease in the temperature of the fluid in the keg will result in a drop in pressure and a concomitant injection of additional supplemental gas; a subsequent increase in temperature will result in an increase in pressure without a suitable release of gas.
Mechanical pressure relief valves are designed to prevent rupture of the keg and are generally insufficient to prevent over-pressurization of the beer, especially low-carbonation ales and the like.
A further drawback of such systems is the unpopularity of CO2 high-pressure cartridges, especially for persons who buy party beer kegs only occasionally, as it is not worthwhile to procure an expensive tap fitting. Some people are even uncomfortable handling high-pressure CO2 cartridges. Others worry about the replacement supply of cartridges. A further drawback of the high pressure cartridges is that they are stored at pressures up to approximately 850 psi, and thus the bottle for storing the liquid to be carbonated must be a fairly heavy, thick-walled apparatus. Such systems were and are commonly used to make seltzer water. However, such heavy pressure bottles are expensive and relatively awkward to handle.
Therefore, there is a need in the art for a system and method that allows a user to alter the pressure of a beverage container during regular use, without the need for a large and separate supply of pressurized gas does not require the use of significant power.
The present invention solves these and other problems in the prior art.